Question: $ { \left[\begin{array}{rrr}{3} & {2} & {3} \\ {1} & {3} & {1}\end{array}\right]+\left[\begin{array}{rrr}{-1} & {-2} & {-1} \\ {4} & {3} & {4}\end{array}\right] = {?} } $
To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{rrr}{3}+{-1} & {2}+{-2} & {3}+{-1} \\ {1}+{4} & {3}+{3} & {1}+{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{2} & {0} & {2} \\ {5} & {6} & {5}\end{array}\right]}$